title: Determination of metformin and other biguanides in forensic whole blood samples by hydrophilic interaction liquid chromatography-electrospray tandem mass spectrometry.
abstract: Metformin is an anti-diabetic drug in the biguanide class which also includes phenformin and buformin. Because of the potential adverse effects of the biguanides, a reliable liquid chromatography-tandem mass spectrometry method using pneumatically assisted electrospray ionization was developed for the quantification of the drugs in both live and post-mortem human whole blood. The blood proteins were precipitated by the addition of a mixture of methanol and acetonitrile, and the extract was cleaned up by cation-exchange solid-phase extraction to eliminate ion suppression effects. The separation was performed by hydrophilic interaction liquid chromatography. Matrix-matched calibrants combined with isotope dilution of metformin were used for calibration. The detection limits were 0.01 mg/L for metformin and phenformin and the relative intra-laboratory reproducibility standard deviations were less than 6% at concentrations of 1-10 mg/L. The mean true recoveries were greater than 86%.
authors.affiliation: Section for Toxicology and Drug Analysis, Department of Forensic Medicine, Aarhus University, Brendstrupgaardsvej 100, Aarhus N, Denmark. lks@forensic.au.dk
authors.forename: Lambert K
authors.initials: LK
authors.lastname: Sørensen
mesh_terms: D000097:Acetonitriles; D001344:Autopsy; D001645:Biguanides / Q000097:blood*; D002853:Chromatography, Liquid / Q000379:methods*; D044707:Forensic Sciences / Q000379:methods; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D057230:Limit of Detection; D016014:Linear Models; D008687:Metformin / Q000097:blood*; D000432:Methanol; D015203:Reproducibility of Results; D052616:Solid Phase Extraction; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D000097:Acetonitriles; D001645:Biguanides; D008687:Metformin; D000432:Methanol; C032159:acetonitrile